Monolith adsorbents for air separation processes

ABSTRACT

An improved method for preparing an adsorbent containing sheet is disclosed. Deionized water is employed in a slurry during preparation of the adsorbent containing sheet. The treated adsorbent monoliths provide improved sorption capacity and N 2 /O 2  selectivity when employed in gas separation processes.

This application is a continuation-in-part of Ser. No. 09/664,568, filedSep. 18, 2000.

FIELD OF THE INVENTION

The present invention provides for methods for preparing an adsorbentcontaining sheet, their preparation into adsorbent monoliths and theirsubsequent use in air separation processes. More particularly, thepresent invention relates to the use of alkali or alkaline metal saltsor mixtures thereof in preparing zeolite containing adsorbent sheetswhich can be used to construct monolith structures.

BACKGROUND OF THE INVENTION

Cyclic adsorption processes are frequently used to separate thecomponents of a gas mixture. Typically, cyclic adsorption processes areconducted in one or more adsorbent vessels that are packed with aparticulate adsorbent material which adsorbs at least one gaseouscomponent of the gas mixture more strongly than it adsorbs at least oneother component of the mixture. The adsorption process comprisesrepeatedly performing a series of steps, the specific steps of thesequence depending upon the particular cyclic adsorption process beingcarried out.

In any cyclic adsorption process, the adsorbent bed has a finitecapacity to adsorb a given gaseous component and, therefore, theadsorbent requires periodic regeneration to restore its adsorptioncapacity. The procedure followed for regenerating the adsorbent variesaccording to the process. In VSA processes, the adsorbent is at leastpartially regenerated by creating vacuum in the adsorption vessel,thereby causing adsorbed component to be desorbed from the adsorbent,whereas in PSA processes, the adsorbent is regenerated at atmosphericpressure. In both VSA and PSA processes, the adsorption step is carriedout at a pressure higher than the desorption or regeneration pressure.

A typical VSA process generally comprises of a series of four basicsteps that includes (i) pressurization of the bed to the requiredpressure, (ii) production of the product gas at required purity, (iii)evacuation of the bed to a certain minimum pressure, and (iv) purgingthe bed with product gas under vacuum conditions. In addition a pressureequalization or bed balance step may also be present. This stepbasically minimizes vent losses and helps in improving processefficiency. The PSA process is similar but differs in that the bed isdepressurized to atmospheric pressure and then purged with product gasat atmospheric pressure.

As mentioned above, the regeneration process includes a purge stepduring which a gas stream that is depleted in the component to bedesorbed is passed countercurrently through the bed of adsorbent,thereby reducing the partial pressure of adsorbed component in theadsorption vessel which causes additional adsorbed component to bedesorbed from the adsorbent. The nonadsorbed gas product may be used topurge the adsorbent beds since this gas is usually quite depleted in theadsorbed component of the feed gas mixture. It often requires aconsiderable quantity of purge gas to adequately regenerate theadsorbent. For example, it is not unusual to use half of the nonadsorbedproduct gas produced during the previous production step to restore theadsorbent to the desired extent. The purge gas requirement in both VSAand PSA processes are optimization parameters and depend on the specificdesign of the plant and within the purview of one having ordinary skillin the art of gas separation.

Many process improvements have been made to this simple cycle design inorder to reduce power consumption, improve product recovery and purity,and increase product flowrate. These have included multi-bed processes,single-column rapid pressure swing adsorption and, more recently,piston-driven rapid pressure swing adsorption and radial flow rapidpressure swing adsorption. The trend toward shorter cycle times isdriven by the desire to design more compact processes with lower capitalcosts and lower power requirements. The objective has been to develop anadsorbent configuration that demonstrates a low pressure drop, a fastpressurization time and an ability to produce the required purity ofoxygen.

For the details as to the manufacture of adsorbent sheets and theconstruction of monoliths used for dehumidification purposes, referenceis made to U.S. Pat. Nos. 5,660,048, 5,660,221, 5,685,897, 5,580,369 and4,012,206. The adsorption wheels are fabricated from an adsorbent paperwhich contains a adsorbent material. The adsorbent paper is preparedfrom a natural or synthetic fiber material. This fiber material can becombined with the adsorbent and wet-laid into a continuous sheet orhandsheet. This wet-laying is achieved by forming a slurry of the fiber,the adsorbent and binder components in water. This slurry is thentransferred to a handsheet mold or to the head box of a continuous wirepaper machine for introduction onto the Fourdrinier or Twin-Wire papermachine. The adsorbent can contain zeolites, silica gels and/or alumina.

In a typical papermaking process, plenty of water from rivers, lakes ormunicipality supplies is used. When zeolite needs to be incorporatedinto the paper, these large quantities of water will have two negativeeffects on the performance of zeolite in a separation process. The firstarises from the ion exchange of cations between the process water andzeolite and second one is the hydrolysis of zeolite cations leading to aprotonic exchange. If the papermaking process is carried out at highertemperatures, the hydrolysis of zeolitic cations will be even moresignificant. Depending on the type of separation or catalyticapplication, the modification in chemical composition of zeolite canhave dramatic effect on the performance.

Li-containing molecular sieves are widely used in air separation processto selectively adsorb N₂ over O₂, thereby producing O₂ in a continuousprocess in a multiple bed operation. If the process water containscations such as Na, Ca and Mg, which are found in typical water suppliesthe exchange of these cations into Li-sieve will lead a decrease in theLi content of zeolite and consequently a decrease on the sorptioncapacity of N₂ and a decrease in N₂/O₂ selectivity. However, if thesorbate molecule has stronger interaction with cations, such as water asin a dehumidification application, the partial ion-exchange of zeolitecations from the process water may not have significant influence on theperformance of the adsorbent. Hence, in an adsorption process involvingweaker interactions, retaining the preferred original composition of thezeolite during the papermaking process is very crucial.

The present invention provides means to keep the original composition ofthe adsorbent by preventing the leaching of cations from the zeoliteboth during the preparation of stock preparation, and during and afterthe manufacture of the paper. It also describes a method for decreasingthe hydrolysis of zeolite cations, when a slurry containing zeolite iscoated or impregnated on to various substrates.

SUMMARY OF THE INVENTION

The present invention provides for an improved method for preparing anadsorbent containing sheet by the addition of alkali and alkaline metalsalts or mixtures thereof to the adsorbent containing slurry sheet.These salts can be added to either the slurry during its preparation orby post-treating the monolithic structures with an aqueous solution ofthe metal salt. It also discloses using deionized water in place ofriver or lake water, which were typically used in paper industry.

The present invention further provides for an improvement by adding themetal salt to a zeolite containing slurry which will be coated to asubstrate such as a flat sheet, corrugated sheet, metal foil or mesh.

The monolith adsorbents that have been prepared in this mannerdemonstrate improved nitrogen capacity and nitrogen/oxygen selectivityin air separation processes such as vacuum swing adsorption (VSA) orpressure swing adsorption (PSA) processes.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for a method of preparing an adsorbentcontaining sheet comprising the steps of:

(a) mixing together a slurry of fiber, adsorbent, retention aid, and abinder in deionized water;

(b) adding to the slurry an alkali or alkaline metal salt or mixturesthereof;

(c) removing the water from the slurry; and

(d) forming the adsorbent containing sheet.

In an alternative embodiment, a monolith adsorbent is prepared bywashing the monolith adsorbent with a solution of an alkali or alkalinemetal salt or mixtures thereof. In a further alternative embodiment, theslurry may comprise water, fiber and adsorbent and the alkali oralkaline metal salt or mixtures thereof is added to the slurry prior tothe addition of the other papermaking chemical additives such asdry-strength adhesives, wet strength resins, defoamers, retention anddrainage aids. Although these methods of addition are preferred, themetal salt can be added at any stage during the slurry or stockpreparation process.

The present invention also provides for an improved method of preparingand adsorbent containing sheet from a slurry comprising a mixture offiber, binder, adsorbent and retention aid in deionized water. Theimproved slurry may also be applied to a substrate resulting in animproved adsorbent.

In the process of the present invention, a slurry is first formed usingdeionized (DI) water. The mixing container is typically a mild steel orstainless steel tank or a polymer-lined vessel. The use of DI waterprevents cations contained in other sources of water from replacing thecations in the adsorbent zeolite. A slurry is made by adding fiber,which can be either synthetic or natural, to the DI water. The adsorbentmaterial, which is typically a zeolite, is then added to the fiberslurry either in the powder form or by mixing with water. In thefollowing stages, a binder, a retention aid and optionally a porefilling agent are added.

The synthetic organic polymeric fibers include aromatic polyamides,polyesters, polyvinyl chlorides, nylons, acrylics, polyethylenes,polypropylenes, acrylonitrile homopolymers, copolymers with halogenatedmonomers, styrene copolymers, and mixtures of polymers (polypropylenewith low-density polyethylene, and high density polyethylene withpolystyrene). The inorganic fibers include glass or metal fibers androck wool etc. The natural fibers include wood pulp such as cellulose.Combination of organic and inorganic fibers can also be used.

The retention aid can be any material that is added to the stock toincrease the retention of adsorbent. Various types of additives such asinorganic salts and organic polyelectrolytes can be useful as retentionaids in papermaking.

In addition to retention aids, a binder can be added to add strength andspecialized properties, such as flexibility to the finished sheets.

The preferred polymeric organic binders are starch, polyvinyl alcohols,acrylics, polyurethane, polyethylene glycol, polypropylene glycol,polyacrylic acid, polyamide and polyamine. Non polymeric binders havinga functionality of a carboxylic acid, an aldehyde, an amino acid, anamine, and an amine can also be used. In general, these polymeric andnon-polymeric binders have a hydrogen bonding functionality orcoordinate covalent bond forming functionality to bind to fibers andzeolite particles. Inorganic binders such as silica and mineralsilicates can also be used.

The adsorbent material is preferably a zeolite of type X, type A, ZSM-3,EMT, EMC-2, ZSM-18, ZK-5, ZSM-5, ZSM-11, β, L, chabazite, offretite,erionite, mordenite, gmelinite, mazzite, and mixtures thereof. Thecations in zeolites can be exchanged to modify the adsorption behavior.The selectivity for a given sorbate molecule depends on both the zeolitestructure as well as the number and nature of the cations in zeolite.Hence same zeolite can be applied in different separation processes byexchanging with other cations. Cation exchange can also modify the poresize of the zeolite enabling the separation of molecules based on thesize.

The temperature at which the stock preparation and handsheet making willbe done depends on the nature of binder, flocculation agent, porefilling agent or any other chemical adhesive. Typically the process iscarried out in between 25 and 80° C.

The dried adsorbent material is then formed into the appropriate shape.In one embodiment of the invention, a flat sheet was bonded to acorrugated sheet to form a single-faced corrugated sheet, which is thenspirally wrapped to make a monolith structure containing plurality ofparallel channels. In another embodiment of the invention, the flatsheets are spirally wound with alternating layers of spacers.

The improvement comprises adding to the slurry an alkali or alkalinemetal salt or mixtures thereof. The metal salt will inhibit the leachingof cations from the adsorbent material. Additionally the metal salt willmaintain the pH in a basic range and will inhibit the hydrolysis ofcations in the adsorbent material.

The retention of adsorbent in the handsheets is hardly effected by theaddition of these salts. Typically, handsheets can contain up to 90 wt.% of adsorbent, the remainder being fibrous material and other chemicaladhesives, mainly the binder.

The alkali or alkaline metal salts have cations that are selected fromthe group consisting of Group IA, Group IIA, Group IB, Group IIB andGroup IIIB of the periodic table. The anions employed to form thesemetal salts are selected from the group consisting of hydroxide,chloride, nitrate, sulfate, carbonate, alkoxide and acetate.

In an alternative embodiment, the final formed monolith structure iswashed with an alkali or alkaline metal salt or mixtures thereof. Thesalt solution may be applied as a wash by spraying or it may be appliedby immersing the formed monolith structure into a solution of the salt.

In another alternative embodiment, a slurry which comprises a binder, anadsorbent, and preferably a pore filling agent and a suspending agent indeionized water can be applied to a substrate. The improvement lies inadding to this slurry an alkali or an alkaline metal salt or mixturesthereof.

The substrate which can be a woven or non-woven material includes but isnot limited to flat sheets, corrugated sheets, metal foils and mesheswhich can be metal, glass fiber or synthetic organic polymeric material.Typically the substrate will be about 0.005 inches to about 0.05 inchesthick. The method of application can be by spraying the slurry solutionon the substrate or by immersing or dipping the substrate into acontainer of the solution. The slurry can also be applied to thesubstrate by means of roller printing such as that described in U.S.Pat. No. 5,827,577.

The substrate is then used to construct monolith structures of any shapeand size having abrupt radii and passageways so that the gas goingthrough the passageways will come in contact with the adsorbent.

As described in U.S. Pat. No. 5,496,397, a suspending agent such asN-methyl-2-pyrrolidone, which helps maintain the adsorbent particles insuspension so that the adsorbent particles will not settle out and areevenly distributed in the coating mixture may be added. A pore fillingagent such as isopropyl alcohol may also be added before a binder isadded so that it prevents the occlusion of or blockage of pores by thebinder.

The metal salt may be applied as an aqueous solution, generally made upfrom deionized water. The concentration of salt in the solution can bevaried to impact the desired amount of cations for application to theslurry of formed monolith structure. Typically the metal salt isdissolved to make a solution in a range from about 0.001 N to about 5.0N with a range of about 0.005 to about 1.0, preferred.

The monolith structure when finally formed may take on any design andshape for use in gas separation processes. The formed monolith structuremay include as adsorbents zeolite type X, zeolite type A, ZSM-3, EMT,EMC-2, ZSM-18, ZK-5, ZSM-5, ZSM-11, β, L, chabazite, offretite,erionite, mordenite, gmelinite, and mazzite, as well as mixtures ofthese. Although various cationic forms of zeolites can be chosen,preferably, the adsorbent is a lithium-containing or lithium andbivalent cation-containing, or a lithium and trivalent cation containingzeolite of type A and X, which contains Si/Al molar ratio of 0.9 to1.25, preferably 1.0 to 1.1, and most preferably with an Si/Al ration ofabout 1.0.

In the adsorption process embodiment of the invention, a component of agas mixture that is more strongly adsorbed than other components of thegas mixture is separated from the other components by contacting the gasmixture with the adsorbent under conditions which effect adsorption ofthe strongly adsorbed component. Preferred adsorption processes includePSA, including vacuum swing adsorption (VSA), TSA and combinations ofthese.

The temperature at which the adsorption step of the adsorption processis carried out depends upon a number of factors, such as the particulargases being separated, the particular adsorbent being used, and thepressure at which the adsorption is carried out. In general, theadsorption step of the process is carried out at a temperature of atleast about −190° C., preferably at a temperature of at least about −20°C., and most preferably at a temperature of at least about 0° C. Theupper temperature limit at which the adsorption step of the process iscarried out is generally about 400° C., and the adsorption step ispreferably carried out at temperatures not greater than about 70° C.,and most preferably carried out at temperatures not greater than about50° C.

The adsorption step of the process of the invention can be carried outat any of the usual and well known pressures employed for gas phasetemperature swing adsorption and pressure swing adsorption processes.Typically the minimum absolute pressure at which the adsorption step iscarried out is generally about 0.7 bara (bar absolute), preferably about0.8 bara and most preferably about 0.9 bara. The adsorption can becarried out at pressures as high as 50 bara or more, but is preferablycarried out at absolute pressures, and preferably not greater than about20 bara, and most preferably not greater than about 10 bar.

When the adsorption process is PSA, the pressure during the regenerationstep is reduced, usually to an absolute pressure in the range of about0.1 to about 5 bara, and preferably to an absolute pressure in the rangeof about 0.175 to about 2 bara, and most preferably to an absolutepressure in the range of about 0.2 to about 1.1 bara.

As indicated above, the process of the invention can be used to separateany two gases, provided that one of the gases is more strongly adsorbedby the adsorbents of the invention than is the other gas under eitherconditions of equilibrium or non-equilibrium, i. e., in the kineticregime of a process. The process is particularly suitable for separatingnitrogen from oxygen, nitrogen and argon from oxygen, carbon dioxidefrom air, dinitrogen oxide from air and for the separation ofhydrocarbons, for example, the separation of alkenes, such as ethylene,propylene, etc., from alkanes, such as ethane, propane, etc., and theseparation of straight-chain hydrocarbons from branched-chainhydrocarbons, e.g., the separation of n-butane from i-butane. Type Azeolites with appropriate cation compositions are particularly suitablefor the separation of alkenes from alkanes, n-alkanes from i-alkanes andcarbon dioxide from alkanes, alkenes and acetylene. The separation ofthese gases is preferably carried out at ambient temperature or higher,although the separation of nitrogen, oxygen and argon can be carried outat cryogenic temperatures.

It will be appreciated that it is within the scope of the presentinvention to utilize conventional equipment to monitor and automaticallyregulate the flow of gases within the system so that it can be fullyautomated to run continuously in an efficient manner.

The invention is further illustrated by the following examples in which,unless otherwise indicated, parts, percentages and ratios are on aweight basis.

EXAMPLE 1

Lithium and rare-earth containing LSX (LiRELSX) sample was made asdisclosed in the EXAMPLE 1 of U.S. Pat. No. 5,464,467.

EXAMPLES 2-4

Li,RELSX sample prepared in Example 1 was agitated at 50° C. for 2 h inan aqueous solution with different concentrations of LiOH (AldrichChemical Co.). 5.0 g of zeolite was first dispersed in 250 ml of waterand different amounts of LiOH salt was added to get the appropriateconcentration. The concentration of LiOH solution and the resultant pHfor each of the examples are summarized in Table 1.

TABLE 1 The concentration of LiOH solution and the pH in the preparationof LiRELSX samples. Example LiOH concentration, M slurry pH 2 0.000 10.53 0.007 11.0 4 0.015 11.4

EXAMPLE 5

Adsorption isotherms of nitrogen (N₂) and oxygen (O₂) on the products ofexamples 1-4 were measured gravimetrically using Cahn 2000 Seriesmicrobalance enclosed in a stainless steel vacuum/pressure system. About100 mg of samples carefully evacuated and its temperature increased to450° C. at a rate of 1°-2° C. per minute. The adsorption isotherms fornitrogen and oxygen were measured at 25° C. in the pressure range20-6900 mbar for nitrogen and 20-2000 mbar for oxygen and the datafitted to a single and multiple site langmuir isotherm model. The fitsto the nitrogen data were used to calculate the effective capacity fornitrogen at 25° C. and N₂/O₂ selectivities. The effective nitrogencapacity defined as the difference between the nitrogen capacity at 1000mbar and that at 300 mbar gives a good indication of the capacity of theadsorbent in a PSA process operated between upper and lower pressures inthis range. The selectivities of the samples for nitrogen over oxygen inair at 300 and 1000 mbar and 25° C. were derived from the pure gasisotherms for nitrogen and oxygen using Langmuir mixing rules (Ref. e.g.A. L. Myers: AIChE: 29(4), (1983), p691-693). The usual definition forselectivity was used, where the selectivity (S) is given by:

S=(X_(N2)/Y_(N2))/(X_(O2)/Y_(O2))

where X_(N2) and X_(O2) are the mole fractions of nitrogen and oxygen,respectively, in the adsorbed phases, and Y_(N2) and Y_(O2) are the molefractions of nitrogen and oxygen, respectively, in the gas phase.

The adsorption results for the samples from examples 1-4 are given Table2.

TABLE 2 Adsorption capacities of LiRELSX powders washed with watercontaining different amount of LiOH* Effective N₂ capacity N₂/O₂selectivity Sample Name mmol/g 1000 mbar 300 mbar LiRELSX-example 10.589 6.1 9.3 LiRELSX-example 2 0.515 5.4 7.9 LiRELSX-example 3 0.5805.9 8.6 LiRELSX-example 4 0.605 6.2 9.1

EXAMPLE 6

The samples from examples 1-4 were analyzed by Inductively CoupledPlasma Atomic Emission Spectroscopy (ICP-AES) using an ARL-3510Sequential spectrometer. The relative Li content of these samples,washed in an aqueous solution containing amounts of LiOH, is comparedwith parent LiRELSX samples in Table 3. The relative Li content definedas the amount of Li present in the washed LiRELSX as compared to theparent LiRELSX sample.

TABLE 3 Composition of LiRELSX samples prepared in examples 1-4. SampleRelative Li content LiRELSX-example 1 1.000 LiRELSX-example 2 0.912LiRELSX-example 3 0.968 LiRELSX-example 4 1.027

EXAMPLE 7

A slurry was made by adding a fibrillated or non-fibrillated fiber tothe DI water. An adsorbent containing slurry, prepared by adding DIwater to LiRELSX zeolite, was then added to the above slurry containingfiber under stirring. A retention aid and a binder were added allowingfibers and adsorbent materials to flocculate so that they can be easilyretained on the forming wire. The stock preparation is carried out at47° C. The stock is added to the handsheet mold and water is drained bygravitational forces. The sheet thus formed is pressed by roller pressto remove the water. The sheet was then dried at 100° C. for 5 min.

EXAMPLE 8

Example 7 was repeated with the addition of LiOH salt to thefiber/adsorbent suspension and before the retention aid and binder wereadded.

EXAMPLE 9

Handsheets from examples 7 and 8 were activated at 400° C. for 10 hoursin the flow of nitrogen in the oven and were again activated at 400° C.for 1 h in-situ during adsorption measurements. The effective nitrogencapacity and N_(2/O) ₂ selectivites as defined in example 6 are given inTable 4.

TABLE 4 Influence of the addition of LiOH on adsorption capacity andselectivities of L1-17 embedded sheets Effective N₂ capacity N2/O2selectivity mmol/g 1000 mbar 300 mbar Sheet from example 7 0.569 5.5 7.8Sheet from example 8 0.574 6.5 9.1

EXAMPLE 10

Handsheets were calcined at 580° C. in air to decompose all non-zeoliticmaterial. The resulting white zeolite powder samples from handsheets ofexamples 7 and 8 were analyzed by ICP-AES as described in EXAMPLE 7 andthe results are given in Table 5.

TABLE 5 LiRELSX in handsheet with and without LiOH addition. SampleRelative Li content Sheet from example 7 0.886 Sheet from example 80.964

While this invention has been described with respect to particularembodiments thereof, it is apparent that numerous other forms andmodifications of the invention will be obvious to those skilled in theart. The appended claims and this invention generally should beconstrued to cover all such obvious forms and modifications which arewithin the true spirit and scope of the present invention.

Having thus described the invention, what we claim is:
 1. A method ofpreparing an adsorbent sheet, wherein said adsorbent comprises a lithiumion exchanged type X zeolite from a slurry comprising a mixture of saidadsorbent, binder, fiber, and flocculating agent in deionized water, theimprovement comprising adding to said slurry a lithium salt to inhibitleaching out of lithium ions already present in said adsorbent.
 2. Themethod as claimed in claim 1 wherein said slurry is used to make thesheet either in a laboratory handsheet mold apparatus or a Fourdrinieror Twin-Wire paper machine.
 3. The method as claimed in claim 1 whereinsaid sheet is formed into a shaped monolith adsorbent.
 4. The method asclaimed in claim 1 wherein said type X zeolite contains lithium, lithiumand bivalent cations, or lithium and trivalent cations.
 5. The method asclaimed in claim 1 wherein said type X zeolite has an Si/Al molar ratioof about 0.9 to about 1.25.
 6. The method as claimed in claim 1 whereinsaid X type zeolite has an Si/Al molar ratio of about 1.0 to 1.1.
 7. Themethod as claimed in claim 1 wherein said X type zeolite has an Si/Alratio of about 1.0.
 8. The method as claimed in claim 1 wherein saidtype X zeolite contains lithium, lithium and bivalent cations, orlithium and trivalent cations, and has an Si/Al ratio of about 1.0 to1.1.
 9. The method as claimed in claim 1 where said type X zeolitecontains lithium, lithium and bivalent cations, or lithium and trivalentcations, and the lithium content is greater than 50% of the totalcharge-compensating cations.
 10. The method as claimed in claim 4 wherethe lithium content is greater than 50% of the total charge-compensatingcations.
 11. The method as claimed in claim 9 wherein said type Xzeolite contains lithium, lithium and bivalent cations, or lithium andtrivalent cations, and has an Si/Al ratio of about 1.0 to 1.1.
 12. Themethod as claimed in claim 9 wherein said type X zeolite containslithium, lithium and bivalent cations, or lithium and trivalent cations,and the lithium content is greater than 80% of the totalcharge-compensating cations.
 13. A method for applying a slurrycomprising a binder and a lithium ion exchanged type X zeolite adsorbentto a substrate, the improvement comprising mixing said binder and alithium salt in deionized water prior to applying said slurry to saidsubstrate to inhibit leaching out of lithium ions already present insaid adsorbent.
 14. The method as claimed in claim 13 wherein saidslurry further comprises a pore filling agent.
 15. The method as claimedin claim 14 wherein said slurry further comprises a suspending agent.16. The method as claimed in claim 13 wherein said substrate is selectedfrom the group consisting of flat sheets, corrugated sheets, metalfoils, and meshes selected from the group consisting of metal, glassfiber and polymeric materials.
 17. The method as claimed in claim 13wherein said substrate may contain zeolite particles either or bothsurfaces or sides.
 18. The method as claimed in claim 13 wherein saidslurry is applied by spraying, dipping or roller printing.
 19. Themethod as claimed in claim 13 wherein said type X zeolite containslithium, lithium and bivalent cations, or lithium and trivalent cations.20. The method as claimed in claim 13 wherein said X type zeolite has anSi/Al molar ratio of about 0.9 to about 1.25.
 21. The method as claimedin claim 13 wherein said X type zeolite has an Si/Al molar ratio ofabout 1.0 to 1.1.
 22. The method as claimed in claim 13 wherein said Xtype zeolite has an Si/Al ratio of about 1.0.
 23. The method as claimedin claim 13 wherein said type X zeolite contains lithium, lithium andbivalent cations, or lithium and trivalent cations, and has an Si/Alratio of about 1.0 to 1.1.
 24. The method as claimed in claim 13 wheresaid type X zeolite contains lithium, lithium and bivalent cations, orlithium and trivalent cations, and t he lithium content is greater than50% of the total charge-compensating cations.
 25. The method as claimedin claim 19 where the lithium content is greater than 50% of the totalcharge-compensating cations.
 26. The method as claimed in claim 13wherein said type X zeolite contains lithium, lithium and bivalentcations, or lithium and trivalent cations, and has an Si/Al ratio ofabout 1.0 to 1.1.
 27. The method as claimed in claim 13 wherein saidtype X zeolite contains lithium, lithium and bivalent cations, orlithium and trivalent cations, and the lithium content is greater than80% of the total charge-compensating cations.
 28. A method of separatinga first gaseous component from a gas mixture comprising said firstgaseous component and a second gaseous component comprising: (a) passingthe gaseous mixture into an adsorption zone containing a monolithadsorbent which is formed from an adsorbent containing sheet whereinsaid adsorbent comprises a lithium ion exchanged type X zeolite preparedfrom a slurry comprising a mixture of fiber, binder, said adsorbent andflocculating agent in deionized water and a lithium salt, therebyinhibiting leaching out of lithium ions already present in saidadsorbent; wherein said monolith adsorbent is capable of separating saidfirst gaseous component from said second gaseous component; and (b)recovering the non-preferentially adsorbed gaseous component from saidadsorption zone.
 29. The method as claimed in claim 28 wherein saidgaseous mixture is air and said first and said second gaseous componentsare oxygen and nitrogen.
 30. The method as claimed in claim 28 whereinsaid type X zeolite contains lithium, lithium and bivalent cations, orlithium and trivalent cations.
 31. The method as claimed in claim 28wherein said type X zeolite has an Si/Al molar ratio of about 0.9 toabout 1.25.
 32. The method as claimed in claim 28 wherein said X typezeolite has an Si/Al molar ratio of about 1.0 to 1.1.
 33. The method asclaimed in claim 28 wherein said X type zeolite has an Si/Al ratio ofabout 1.0.
 34. The method as claimed in claim 28 wherein said type Xzeolite contains lithium, lithium and bivalent cations, or lithium andtrivalent cations, and has an Si/Al ratio of about 1.0 to 1.1.
 35. Themethod as claimed in claim 28 wherein the lithium content is greaterthan 50% of the total charge-compensating cations.
 36. The method asclaimed in claim 35 wherein said type X zeolite contains lithium,lithium and bivalent cations, or lithium and trivalent cations, and hasan Si/Al ratio of about 1.0 to 1.1.
 37. The method as claimed in claim36 wherein said type X zeolite contains lithium, lithium and bivalentcations, or lithium and trivalent cations, and the lithium content isgreater than 80% of the total charge-compensating cations.
 38. Themethod as claimed in claim 28 wherein said slurry further comprises abinder.
 39. The method as claimed in claim 28 wherein said slurryfurther comprises a retention aid.
 40. The method as claimed in claim 28wherein said monolith adsorbent is prepared by creating a slurrycomprising a binder, lithium ion exchanged type X zeolite and a lithiumsalt in deionized water, to inhibit the leaching out of lithium ionsalready present in said monolith adsorbent and applying said slurry to asubstrate.